Gas turbine engines are commonly used to generate energy and propulsion in many modern aircraft as well as other vehicles and industrial processes. Many such engines include a fan, compressor, combustor and turbine provided in serial fashion, forming an engine core and arranged along a central longitudinal axis. Air enters the gas turbine engine through the fan and is pressurized in the compressor. This pressurized air is mixed with fuel in the combustor. The fuel-air mixture is then ignited, generating hot combustion gases that flow downstream to the turbine. The turbine is driven by the exhaust gases and mechanically powers the compressor and fan via a central rotating shaft. Energy from the combustion gases not used by the turbine is discharged through an exhaust nozzle, producing thrust to power the aircraft.
In light of this it can be seen that the airfoils of a gas turbine engine, including the fan, compressor, and turbine blades and vanes, are subjected to extreme internal temperatures and weather conditions when the gas turbine engine is in operation. Accordingly, such airfoils need to be manufactured well. This is important not only for efficient, proper operation, but for safe operation as well. For example, given the proximity of such engines to the fuselage of the aircraft, it is important that such blades remain connected to their respective rotor hubs, and in the rare event of dislodgement, that the blades be contained within the engine. In fact, the Federal Aviation Administration requires that gas turbine engines meet certain requirements in this regard and thus sets forth regulations, such as 14 C.F.R. § 33.94, pertaining to blade containment.
One situation, which may be particularly challenging for gas turbine engines in this regard, arises when the engine ingests foreign objects, such as birds or ice. The blades, in such a situation, must be manufactured sufficiently to withstand such impact, and absent that, the engine as a whole must be sufficiently designed to contain such blades if they should become dislodged.
Therefore, it would be advantageous to produce a fan blade of sufficient strength and design to avoid dislodgement, even in the event of foreign object ingestion. Ideally, the fan blade would be designed and built strong enough to not only meet FAA requirements, but to far exceed them as well.